Metamorphism, Metamorphic Processes, And Metamorphic Products Flashcards
The process of change or transformation of a pre-existing rock, in solid state, into another due to heat, pressure, and chemically active fluids.
Metamorphism
A form of metamorphism due to hydrothermal fluids exchanging constituents with an external source.
Metasomatism
Increase in temperature and pressure.
Prograde Metamorphism
Decrease in temperature and pressure.
Retrograde Metamorphism
Metamorphism that affects areas with less than 100 square kilometers.
Local Metamorphism
Metamorphism that affects areas greater than 100 square kilometers.
Regional Metamorphism
Also known as “Protoliths”, are the original rocks from where the produced metamorphic rocks transformed from.
Parent Rocks
The type of metamorphic rock that will be produced can also depend on what their ________ is.
Protolith
Agent of Metamorphism that provides energy for chemical reactions and recrystallization of minerals.
Heat
Agent of Metamorphism that provides stress in equal directions or varying amounts in different directions.
Pressure
Agent of Metamorphism that provides and enhances mobility of ions present.
Chemically Active Fluids
Give the temperature range, pressure range, and depth range for LOW GRADE metamorphism.
Temperature: 200-300 Degrees Celcius
Pressure: 300-600 MegaPascals
Depth: 0-6 kilometres
Give the temperature range, pressure range, and depth range for INTERMEDIATE GRADE metamorphism.
Temperature: 300-500 Degrees Celsius
Pressure: 600-1000 MegaPascals
Depth: 2-20 Kilometeres
Give the temperature range, pressure range, and depth range for HIGH GRADE metamorphism.
Temperature: >500 Degrees Celsius
Pressure: >1000 MegaPascals
Depth: >20 Kilometres
Type of pressure that is also called as confining pressure, is a uniform or isotropic form of pressure, where pressure is equal in all directions, which usually produces equant grains and non-foliated texture of metamorphic rocks.
Hydrostatic Pressure
Hydrostatic pressure is also called as?
Confining Pressure
Is also called as the burying stress, is a non-uniform or anistropic form of pressure, where pressure in unequal in all directions, which usually produces inequant grains in all directions and foliated texture of metamorphic rocks.
Lithostatic Stress
Lithostatic stress is also called as?
Burying Pressure
A variable temperature, low pressure metamorphism that develops locally where hot magma intrudes relatively cold, upper crustal country rock.
Contact Metamorphism
Products of Contact Metamorphism.
Hornfels, Metaquartzite, and Skarn
Type of metamorphism characterized by chemical alteration from circulating fluids within cracks and fissures. Pervasive at ocean spreading ridges that experience tension, thinning, and uplift, causes metasomatism.
Hydrothermal Metamorphism
Products of Hydrothermal Metamorphism.
Alteration Products and Metallic Ore Deposits
Given the major minerals and description, what is the type?
Major Minerals: Albite, Paragonite (Na-rich Mica)
Description: High temperature alteration resulting in Na enrichment.
Albitic
Given the major minerals and description, what is the type?
Major Minerals: Alunite and Sulfate Minerals
Description: Occurs in hot spring environments and gold-copper pophyry deposits by oxidation of sulfate minerals.
Alunitic
Given the major minerals and description, what is the type?
Major Minerals: Kaolinite, Smectite, Illite
Description: Low temperature decomposition of feldspars in acidic conditions and occurs in gold deposits hosted by sedimentary rocks.
Argillic
Given the major minerals and description, what is the type?
Major Minerals: Carbonate Minerals: Calcite, Dolomite and Ankerite, and accessory minerals: Chlorite, Sericite, and Albite.
Description: Replacement by Carbonate Minerals at variable temperatures.
Carbonitization
Given the major minerals and description, what is the type?
Major Minerals: Sericite, Quartz, and Pyrite
Description: Decomposition of silicic rocks and is associated with porphyry copper deposits.
Phyllic
Given the major minerals and description, what is the type?
Major Minerals: Biotite, Potassium Felspar, and Adularia
Description: High temperature alteration in silicic magma, resulting in K enrichment, and commonly underlies phyllic zones.
Potassic
Given the major minerals and description, what is the type?
Major Minerals: Chlorite, Epidote, Actinolite, and Tremolite
Description: Low to moderate temperature decomposition of basic and ultrabasic rocks enriched in pyroxene and amphibole, biotite and plagioclase, and also occurs in gold-copper porphyry deposits.
Propylitic
Given the major minerals and description, what is the type?
Major Minerals: Sericite
Description: Alteration of feldspars.
Sericitic
Given the major minerals and description, what is the type?
Major Minerals: Serpentine and Talc
Description: Low temperature alteration of basic and ultrabasic rocks.
Serpentinization
Given the major minerals and description, what is the type?
Major Minerals: Quartz and Chert
Description: Replacement by silica minerals at variable temperatures.
Silication
Given the major minerals and description, what is the type?
Major Minerals: Albite
Description: Low temperature alteration of Ca-plagioclase to Albite
Spilitization
Given the major minerals and description, what is the type?
Major Minerals: Zeolite Minerals
Description: Low temperature replacement of glass in volcanic rocks.
Zeolitic
Term for fine-grained mica minerals.
Sericite
A regional metamorphism induced by increase in pressure and temperature with non-uniform stress, which produces foliated textures, mostly aerially extensive, and dominates convergent margins and associated fold and thrust belts.
Dynamothermal Metamorphism
Products of Dynamothermal Metamorphism.
Greenschist, Amphibolite, Granulite, Blueschist, and Eclogite
Metamorphism that results from increase in lithostatic stress caused by deep burial of rocks and produces non-foliated textures, affects regional subsiding basins that accumulate thick sequences of sediments and volcanic debris, and usually starts at 300 Degrees Celsius and gradational with diagenesis at depths of about 8 Kilometres.
Burial Metamorphism
Products of Burial Metamorphism.
Non-foliated rocks with low temperature mineral assemblages.
A local form of metamorphism generated by explosive volcanic eruptions or relatively rare collisions of extraterrestrial objects with Earth, causong a high strain rate.
Impact Metamorphism
Producs of impact metamorphism.
Impactites, Breccias, Shocked Quarts Lamellae, Pseudotachylites, Coesite, and Stishovite
Induced primarily by non-uniform stress in fault zones and shear zones, where the high strain rate is mostly local but extend to a regional scale in large faults or shear zones, and most likely occur in the same fault or shear zone.
Dynamic Metamorphism
Products of Dynamic Metamorphism.
Cataclasites, Pseudotachylites, and Mylonites
Given the temperature, pressure, depth, and products, identify which kind of metamorphism is induced.
Temperature: High
Pressure/Depth: Low pressures at shallow depths (0-6 Kilometres)
Products: Non-foliated, fine-grained; Hornfels
Contact
Given the temperature, pressure, depth, and products, identify which kind of metamorphism is induced.
Temperature: High
Pressure/Depth: Moderate pressures
Products: Mg-Fe rich Hydrous Minerals
Hydrothermal
Given the temperature, pressure, depth, and products, identify which kind of metamorphism is induced.
Temperature: Moderate
Pressure/Depth: High pressures over an extensive area at considerable depths (5-20 Kilometres, sometimes >30 Kilometres).
Products: High-grade, foliated metamorphic rocks
Dynamothermal
Given the temperature, pressure, depth, and products, identify which kind of metamorphism is induced.
Temperature: Varying
Pressure/Depth: Varying Pressures and Depth
Products: Non-foliated Metamorphic Rocks
Burial
Given the temperature, pressure, depth, and products, identify which kind of metamorphism is induced.
Temperature: Very High
Pressure/Depth: Very High Pressures at Shallow Depths
Products: High-pressure polymorphs of minerals.
Impact
A low temperature, brittle grain-fracturing process that involves grain size reduction through mechanical grinding, rotation and crushing of rock.
Cataclasis
A fine-grained, non-foliated, clastic metamorphic rock produced by cataclastic processes.
Cataclasite
A ductile grain reduction process that produces oriented grains of smaller diameter.
Mylonitization
A product of mylonitization characterized by grain size reduction via macroscopic scale cataclasis, plastic stretching, and thinning associated with ductile deformation.
Mylonite
Occurs in metamorphic rocks where individual atoms or molecules can migrate in gaseous, liquid, or solid phases from one location in a rock body to a new location.
Diffusion
Involves the dissolution of solid grains under high compressive stress conditions.
Pressolution
An insoluble seam that accumulates as soluble minerals dissolve.
Stylolite
Occurs when existing minerals are transformed under higher temperature and/or pressure conditions, without experiencing a significant change in chemical composition.
Recrystallization
The nucleation and growth of new minerals as pre-existing minerals become unstable due to temperature or pressure changes.
Neocrystallization
Newly formed minerals that are ditinctly larger than the minerals in the surrounding matrix.
Pophyroblasts
The segregation of minerals in an initially homogenous rock due to different physical or chemical characteristics, such as solubility, ductility, mineral growth, or crystallization temperature.
Differentiation
Partially melted rocks that form by quenching under high strain rates in shear zone fractures.
Pseudotachylites
A metamorphic halo in the contact zone that surrounds it, produced from the head of the igneous intrusion, and can range from centimeters to hundreds of meters in diameter.
Aureole
Regional metamorphism is usually associated to?
Covergent and Divergent Plate Boundaries
